1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
5 #include <linux/file.h>
7 #include <linux/slab.h>
8 #include <linux/nospec.h>
9 #include <linux/hugetlb.h>
10 #include <linux/compat.h>
11 #include <linux/io_uring.h>
13 #include <uapi/linux/io_uring.h>
16 #include "openclose.h"
19 struct io_rsrc_update {
26 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
27 struct io_mapped_ubuf **pimu,
28 struct page **last_hpage);
31 #define IORING_MAX_FIXED_FILES (1U << 20)
32 #define IORING_MAX_REG_BUFFERS (1U << 14)
34 static inline bool io_put_rsrc_data_ref(struct io_rsrc_data *rsrc_data)
36 return !--rsrc_data->refs;
39 int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
41 unsigned long page_limit, cur_pages, new_pages;
46 /* Don't allow more pages than we can safely lock */
47 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
49 cur_pages = atomic_long_read(&user->locked_vm);
51 new_pages = cur_pages + nr_pages;
52 if (new_pages > page_limit)
54 } while (!atomic_long_try_cmpxchg(&user->locked_vm,
55 &cur_pages, new_pages));
59 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
62 __io_unaccount_mem(ctx->user, nr_pages);
65 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
68 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
73 ret = __io_account_mem(ctx->user, nr_pages);
79 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
84 static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
85 void __user *arg, unsigned index)
87 struct iovec __user *src;
91 struct compat_iovec __user *ciovs;
92 struct compat_iovec ciov;
94 ciovs = (struct compat_iovec __user *) arg;
95 if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
98 dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
99 dst->iov_len = ciov.iov_len;
103 src = (struct iovec __user *) arg;
104 if (copy_from_user(dst, &src[index], sizeof(*dst)))
109 static int io_buffer_validate(struct iovec *iov)
111 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
114 * Don't impose further limits on the size and buffer
115 * constraints here, we'll -EINVAL later when IO is
116 * submitted if they are wrong.
119 return iov->iov_len ? -EFAULT : 0;
123 /* arbitrary limit, but we need something */
124 if (iov->iov_len > SZ_1G)
127 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
133 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
135 struct io_mapped_ubuf *imu = *slot;
138 if (imu != ctx->dummy_ubuf) {
139 for (i = 0; i < imu->nr_bvecs; i++)
140 unpin_user_page(imu->bvec[i].bv_page);
142 io_unaccount_mem(ctx, imu->acct_pages);
148 static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data,
149 struct io_rsrc_put *prsrc)
151 struct io_ring_ctx *ctx = rsrc_data->ctx;
154 io_post_aux_cqe(ctx, prsrc->tag, 0, 0);
155 rsrc_data->do_put(ctx, prsrc);
158 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
160 struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
161 struct io_rsrc_put *prsrc, *tmp;
163 if (ref_node->inline_items)
164 io_rsrc_put_work_one(rsrc_data, &ref_node->item);
166 list_for_each_entry_safe(prsrc, tmp, &ref_node->item_list, list) {
167 list_del(&prsrc->list);
168 io_rsrc_put_work_one(rsrc_data, prsrc);
172 io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
173 if (io_put_rsrc_data_ref(rsrc_data))
174 complete(&rsrc_data->done);
177 void io_wait_rsrc_data(struct io_rsrc_data *data)
179 if (data && !io_put_rsrc_data_ref(data))
180 wait_for_completion(&data->done);
183 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
185 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
189 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
190 __must_hold(&node->rsrc_data->ctx->uring_lock)
192 struct io_ring_ctx *ctx = node->rsrc_data->ctx;
195 while (!list_empty(&ctx->rsrc_ref_list)) {
196 node = list_first_entry(&ctx->rsrc_ref_list,
197 struct io_rsrc_node, node);
198 /* recycle ref nodes in order */
202 list_del(&node->node);
203 __io_rsrc_put_work(node);
207 static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
209 struct io_rsrc_node *ref_node;
210 struct io_cache_entry *entry;
212 entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
214 ref_node = container_of(entry, struct io_rsrc_node, cache);
216 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
222 INIT_LIST_HEAD(&ref_node->node);
223 INIT_LIST_HEAD(&ref_node->item_list);
224 ref_node->done = false;
225 ref_node->inline_items = 0;
229 void io_rsrc_node_switch(struct io_ring_ctx *ctx,
230 struct io_rsrc_data *data_to_kill)
231 __must_hold(&ctx->uring_lock)
233 WARN_ON_ONCE(io_alloc_cache_empty(&ctx->rsrc_node_cache));
234 WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node);
237 struct io_rsrc_node *rsrc_node = ctx->rsrc_node;
239 rsrc_node->rsrc_data = data_to_kill;
240 list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
242 data_to_kill->refs++;
244 io_put_rsrc_node(ctx, rsrc_node);
245 ctx->rsrc_node = NULL;
249 ctx->rsrc_node = io_rsrc_node_alloc(ctx);
252 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
254 if (io_alloc_cache_empty(&ctx->rsrc_node_cache)) {
255 struct io_rsrc_node *node = kzalloc(sizeof(*node), GFP_KERNEL);
259 io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache);
264 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
265 struct io_ring_ctx *ctx)
269 /* As we may drop ->uring_lock, other task may have started quiesce */
272 ret = io_rsrc_node_switch_start(ctx);
275 io_rsrc_node_switch(ctx, data);
277 /* kill initial ref */
278 if (io_put_rsrc_data_ref(data))
281 data->quiesce = true;
282 mutex_unlock(&ctx->uring_lock);
284 ret = io_run_task_work_sig(ctx);
286 mutex_lock(&ctx->uring_lock);
290 /* restore the master reference */
295 ret = wait_for_completion_interruptible(&data->done);
297 mutex_lock(&ctx->uring_lock);
301 * it has been revived by another thread while
304 mutex_unlock(&ctx->uring_lock);
307 data->quiesce = false;
312 static void io_free_page_table(void **table, size_t size)
314 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
316 for (i = 0; i < nr_tables; i++)
321 static void io_rsrc_data_free(struct io_rsrc_data *data)
323 size_t size = data->nr * sizeof(data->tags[0][0]);
326 io_free_page_table((void **)data->tags, size);
330 static __cold void **io_alloc_page_table(size_t size)
332 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
333 size_t init_size = size;
336 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
340 for (i = 0; i < nr_tables; i++) {
341 unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
343 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
345 io_free_page_table(table, init_size);
353 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
354 rsrc_put_fn *do_put, u64 __user *utags,
355 unsigned nr, struct io_rsrc_data **pdata)
357 struct io_rsrc_data *data;
361 data = kzalloc(sizeof(*data), GFP_KERNEL);
364 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
372 data->do_put = do_put;
376 for (i = 0; i < nr; i++) {
377 u64 *tag_slot = io_get_tag_slot(data, i);
379 if (copy_from_user(tag_slot, &utags[i],
384 init_completion(&data->done);
388 io_rsrc_data_free(data);
392 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
393 struct io_uring_rsrc_update2 *up,
396 u64 __user *tags = u64_to_user_ptr(up->tags);
397 __s32 __user *fds = u64_to_user_ptr(up->data);
398 struct io_rsrc_data *data = ctx->file_data;
399 struct io_fixed_file *file_slot;
403 bool needs_switch = false;
407 if (up->offset + nr_args > ctx->nr_user_files)
410 for (done = 0; done < nr_args; done++) {
413 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
414 copy_from_user(&fd, &fds[done], sizeof(fd))) {
418 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
422 if (fd == IORING_REGISTER_FILES_SKIP)
425 i = array_index_nospec(up->offset + done, ctx->nr_user_files);
426 file_slot = io_fixed_file_slot(&ctx->file_table, i);
428 if (file_slot->file_ptr) {
429 file = (struct file *)(file_slot->file_ptr & FFS_MASK);
430 err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file);
433 file_slot->file_ptr = 0;
434 io_file_bitmap_clear(&ctx->file_table, i);
444 * Don't allow io_uring instances to be registered. If
445 * UNIX isn't enabled, then this causes a reference
446 * cycle and this instance can never get freed. If UNIX
447 * is enabled we'll handle it just fine, but there's
448 * still no point in allowing a ring fd as it doesn't
449 * support regular read/write anyway.
451 if (io_is_uring_fops(file)) {
456 err = io_scm_file_account(ctx, file);
461 *io_get_tag_slot(data, i) = tag;
462 io_fixed_file_set(file_slot, file);
463 io_file_bitmap_set(&ctx->file_table, i);
468 io_rsrc_node_switch(ctx, data);
469 return done ? done : err;
472 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
473 struct io_uring_rsrc_update2 *up,
474 unsigned int nr_args)
476 u64 __user *tags = u64_to_user_ptr(up->tags);
477 struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
478 struct page *last_hpage = NULL;
479 bool needs_switch = false;
485 if (up->offset + nr_args > ctx->nr_user_bufs)
488 for (done = 0; done < nr_args; done++) {
489 struct io_mapped_ubuf *imu;
490 int offset = up->offset + done;
493 err = io_copy_iov(ctx, &iov, iovs, done);
496 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
500 err = io_buffer_validate(&iov);
503 if (!iov.iov_base && tag) {
507 err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
511 i = array_index_nospec(offset, ctx->nr_user_bufs);
512 if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
513 err = io_queue_rsrc_removal(ctx->buf_data, i,
514 ctx->rsrc_node, ctx->user_bufs[i]);
516 io_buffer_unmap(ctx, &imu);
519 ctx->user_bufs[i] = ctx->dummy_ubuf;
523 ctx->user_bufs[i] = imu;
524 *io_get_tag_slot(ctx->buf_data, offset) = tag;
528 io_rsrc_node_switch(ctx, ctx->buf_data);
529 return done ? done : err;
532 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
533 struct io_uring_rsrc_update2 *up,
539 lockdep_assert_held(&ctx->uring_lock);
541 if (check_add_overflow(up->offset, nr_args, &tmp))
543 err = io_rsrc_node_switch_start(ctx);
548 case IORING_RSRC_FILE:
549 return __io_sqe_files_update(ctx, up, nr_args);
550 case IORING_RSRC_BUFFER:
551 return __io_sqe_buffers_update(ctx, up, nr_args);
556 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
559 struct io_uring_rsrc_update2 up;
563 memset(&up, 0, sizeof(up));
564 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
566 if (up.resv || up.resv2)
568 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
571 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
572 unsigned size, unsigned type)
574 struct io_uring_rsrc_update2 up;
576 if (size != sizeof(up))
578 if (copy_from_user(&up, arg, sizeof(up)))
580 if (!up.nr || up.resv || up.resv2)
582 return __io_register_rsrc_update(ctx, type, &up, up.nr);
585 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
586 unsigned int size, unsigned int type)
588 struct io_uring_rsrc_register rr;
590 /* keep it extendible */
591 if (size != sizeof(rr))
594 memset(&rr, 0, sizeof(rr));
595 if (copy_from_user(&rr, arg, size))
597 if (!rr.nr || rr.resv2)
599 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
603 case IORING_RSRC_FILE:
604 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
606 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
607 rr.nr, u64_to_user_ptr(rr.tags));
608 case IORING_RSRC_BUFFER:
609 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
611 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
612 rr.nr, u64_to_user_ptr(rr.tags));
617 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
619 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
621 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
623 if (sqe->rw_flags || sqe->splice_fd_in)
626 up->offset = READ_ONCE(sqe->off);
627 up->nr_args = READ_ONCE(sqe->len);
630 up->arg = READ_ONCE(sqe->addr);
634 static int io_files_update_with_index_alloc(struct io_kiocb *req,
635 unsigned int issue_flags)
637 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
638 __s32 __user *fds = u64_to_user_ptr(up->arg);
643 if (!req->ctx->file_data)
646 for (done = 0; done < up->nr_args; done++) {
647 if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
657 ret = io_fixed_fd_install(req, issue_flags, file,
658 IORING_FILE_INDEX_ALLOC);
661 if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
662 __io_close_fixed(req->ctx, issue_flags, ret);
673 int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
675 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
676 struct io_ring_ctx *ctx = req->ctx;
677 struct io_uring_rsrc_update2 up2;
680 up2.offset = up->offset;
687 if (up->offset == IORING_FILE_INDEX_ALLOC) {
688 ret = io_files_update_with_index_alloc(req, issue_flags);
690 io_ring_submit_lock(ctx, issue_flags);
691 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
693 io_ring_submit_unlock(ctx, issue_flags);
698 io_req_set_res(req, ret, 0);
702 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
703 struct io_rsrc_node *node, void *rsrc)
705 u64 *tag_slot = io_get_tag_slot(data, idx);
706 struct io_rsrc_put *prsrc;
707 bool inline_item = true;
709 if (!node->inline_items) {
711 node->inline_items++;
713 prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
719 prsrc->tag = *tag_slot;
723 list_add(&prsrc->list, &node->item_list);
727 void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
731 for (i = 0; i < ctx->nr_user_files; i++) {
732 struct file *file = io_file_from_index(&ctx->file_table, i);
734 /* skip scm accounted files, they'll be freed by ->ring_sock */
735 if (!file || io_file_need_scm(file))
737 io_file_bitmap_clear(&ctx->file_table, i);
741 #if defined(CONFIG_UNIX)
742 if (ctx->ring_sock) {
743 struct sock *sock = ctx->ring_sock->sk;
746 while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
750 io_free_file_tables(&ctx->file_table);
751 io_file_table_set_alloc_range(ctx, 0, 0);
752 io_rsrc_data_free(ctx->file_data);
753 ctx->file_data = NULL;
754 ctx->nr_user_files = 0;
757 int io_sqe_files_unregister(struct io_ring_ctx *ctx)
759 unsigned nr = ctx->nr_user_files;
766 * Quiesce may unlock ->uring_lock, and while it's not held
767 * prevent new requests using the table.
769 ctx->nr_user_files = 0;
770 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
771 ctx->nr_user_files = nr;
773 __io_sqe_files_unregister(ctx);
778 * Ensure the UNIX gc is aware of our file set, so we are certain that
779 * the io_uring can be safely unregistered on process exit, even if we have
780 * loops in the file referencing. We account only files that can hold other
781 * files because otherwise they can't form a loop and so are not interesting
784 int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
786 #if defined(CONFIG_UNIX)
787 struct sock *sk = ctx->ring_sock->sk;
788 struct sk_buff_head *head = &sk->sk_receive_queue;
789 struct scm_fp_list *fpl;
792 if (likely(!io_file_need_scm(file)))
796 * See if we can merge this file into an existing skb SCM_RIGHTS
797 * file set. If there's no room, fall back to allocating a new skb
800 spin_lock_irq(&head->lock);
801 skb = skb_peek(head);
802 if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
803 __skb_unlink(skb, head);
806 spin_unlock_irq(&head->lock);
809 fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
813 skb = alloc_skb(0, GFP_KERNEL);
819 fpl->user = get_uid(current_user());
820 fpl->max = SCM_MAX_FD;
823 UNIXCB(skb).fp = fpl;
825 skb->scm_io_uring = 1;
826 skb->destructor = unix_destruct_scm;
827 refcount_add(skb->truesize, &sk->sk_wmem_alloc);
830 fpl = UNIXCB(skb).fp;
831 fpl->fp[fpl->count++] = get_file(file);
832 unix_inflight(fpl->user, file);
833 skb_queue_head(head, skb);
839 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
841 struct file *file = prsrc->file;
842 #if defined(CONFIG_UNIX)
843 struct sock *sock = ctx->ring_sock->sk;
844 struct sk_buff_head list, *head = &sock->sk_receive_queue;
848 if (!io_file_need_scm(file)) {
853 __skb_queue_head_init(&list);
856 * Find the skb that holds this file in its SCM_RIGHTS. When found,
857 * remove this entry and rearrange the file array.
859 skb = skb_dequeue(head);
861 struct scm_fp_list *fp;
864 for (i = 0; i < fp->count; i++) {
867 if (fp->fp[i] != file)
870 unix_notinflight(fp->user, fp->fp[i]);
871 left = fp->count - 1 - i;
873 memmove(&fp->fp[i], &fp->fp[i + 1],
874 left * sizeof(struct file *));
881 __skb_queue_tail(&list, skb);
891 __skb_queue_tail(&list, skb);
893 skb = skb_dequeue(head);
896 if (skb_peek(&list)) {
897 spin_lock_irq(&head->lock);
898 while ((skb = __skb_dequeue(&list)) != NULL)
899 __skb_queue_tail(head, skb);
900 spin_unlock_irq(&head->lock);
907 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
908 unsigned nr_args, u64 __user *tags)
910 __s32 __user *fds = (__s32 __user *) arg;
919 if (nr_args > IORING_MAX_FIXED_FILES)
921 if (nr_args > rlimit(RLIMIT_NOFILE))
923 ret = io_rsrc_node_switch_start(ctx);
926 ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
931 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
932 io_rsrc_data_free(ctx->file_data);
933 ctx->file_data = NULL;
937 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
938 struct io_fixed_file *file_slot;
940 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
944 /* allow sparse sets */
945 if (!fds || fd == -1) {
947 if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
958 * Don't allow io_uring instances to be registered. If UNIX
959 * isn't enabled, then this causes a reference cycle and this
960 * instance can never get freed. If UNIX is enabled we'll
961 * handle it just fine, but there's still no point in allowing
962 * a ring fd as it doesn't support regular read/write anyway.
964 if (io_is_uring_fops(file)) {
968 ret = io_scm_file_account(ctx, file);
973 file_slot = io_fixed_file_slot(&ctx->file_table, i);
974 io_fixed_file_set(file_slot, file);
975 io_file_bitmap_set(&ctx->file_table, i);
978 /* default it to the whole table */
979 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
980 io_rsrc_node_switch(ctx, NULL);
983 __io_sqe_files_unregister(ctx);
987 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
989 io_buffer_unmap(ctx, &prsrc->buf);
993 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
997 for (i = 0; i < ctx->nr_user_bufs; i++)
998 io_buffer_unmap(ctx, &ctx->user_bufs[i]);
999 kfree(ctx->user_bufs);
1000 io_rsrc_data_free(ctx->buf_data);
1001 ctx->user_bufs = NULL;
1002 ctx->buf_data = NULL;
1003 ctx->nr_user_bufs = 0;
1006 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
1008 unsigned nr = ctx->nr_user_bufs;
1015 * Quiesce may unlock ->uring_lock, and while it's not held
1016 * prevent new requests using the table.
1018 ctx->nr_user_bufs = 0;
1019 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
1020 ctx->nr_user_bufs = nr;
1022 __io_sqe_buffers_unregister(ctx);
1027 * Not super efficient, but this is just a registration time. And we do cache
1028 * the last compound head, so generally we'll only do a full search if we don't
1031 * We check if the given compound head page has already been accounted, to
1032 * avoid double accounting it. This allows us to account the full size of the
1033 * page, not just the constituent pages of a huge page.
1035 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
1036 int nr_pages, struct page *hpage)
1040 /* check current page array */
1041 for (i = 0; i < nr_pages; i++) {
1042 if (!PageCompound(pages[i]))
1044 if (compound_head(pages[i]) == hpage)
1048 /* check previously registered pages */
1049 for (i = 0; i < ctx->nr_user_bufs; i++) {
1050 struct io_mapped_ubuf *imu = ctx->user_bufs[i];
1052 for (j = 0; j < imu->nr_bvecs; j++) {
1053 if (!PageCompound(imu->bvec[j].bv_page))
1055 if (compound_head(imu->bvec[j].bv_page) == hpage)
1063 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
1064 int nr_pages, struct io_mapped_ubuf *imu,
1065 struct page **last_hpage)
1069 imu->acct_pages = 0;
1070 for (i = 0; i < nr_pages; i++) {
1071 if (!PageCompound(pages[i])) {
1076 hpage = compound_head(pages[i]);
1077 if (hpage == *last_hpage)
1079 *last_hpage = hpage;
1080 if (headpage_already_acct(ctx, pages, i, hpage))
1082 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
1086 if (!imu->acct_pages)
1089 ret = io_account_mem(ctx, imu->acct_pages);
1091 imu->acct_pages = 0;
1095 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
1097 unsigned long start, end, nr_pages;
1098 struct vm_area_struct **vmas = NULL;
1099 struct page **pages = NULL;
1100 int i, pret, ret = -ENOMEM;
1102 end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1103 start = ubuf >> PAGE_SHIFT;
1104 nr_pages = end - start;
1106 pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
1110 vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
1116 mmap_read_lock(current->mm);
1117 pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
1119 if (pret == nr_pages) {
1120 struct file *file = vmas[0]->vm_file;
1122 /* don't support file backed memory */
1123 for (i = 0; i < nr_pages; i++) {
1124 if (vmas[i]->vm_file != file) {
1130 if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
1137 ret = pret < 0 ? pret : -EFAULT;
1139 mmap_read_unlock(current->mm);
1142 * if we did partial map, or found file backed vmas,
1143 * release any pages we did get
1146 unpin_user_pages(pages, pret);
1154 pages = ERR_PTR(ret);
1159 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
1160 struct io_mapped_ubuf **pimu,
1161 struct page **last_hpage)
1163 struct io_mapped_ubuf *imu = NULL;
1164 struct page **pages = NULL;
1167 int ret, nr_pages, i;
1168 struct folio *folio = NULL;
1170 *pimu = ctx->dummy_ubuf;
1175 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
1177 if (IS_ERR(pages)) {
1178 ret = PTR_ERR(pages);
1183 /* If it's a huge page, try to coalesce them into a single bvec entry */
1185 folio = page_folio(pages[0]);
1186 for (i = 1; i < nr_pages; i++) {
1187 if (page_folio(pages[i]) != folio) {
1194 * The pages are bound to the folio, it doesn't
1195 * actually unpin them but drops all but one reference,
1196 * which is usually put down by io_buffer_unmap().
1197 * Note, needs a better helper.
1199 unpin_user_pages(&pages[1], nr_pages - 1);
1204 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
1208 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
1210 unpin_user_pages(pages, nr_pages);
1214 off = (unsigned long) iov->iov_base & ~PAGE_MASK;
1215 size = iov->iov_len;
1216 /* store original address for later verification */
1217 imu->ubuf = (unsigned long) iov->iov_base;
1218 imu->ubuf_end = imu->ubuf + iov->iov_len;
1219 imu->nr_bvecs = nr_pages;
1224 bvec_set_page(&imu->bvec[0], pages[0], size, off);
1227 for (i = 0; i < nr_pages; i++) {
1230 vec_len = min_t(size_t, size, PAGE_SIZE - off);
1231 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
1242 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
1244 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
1245 return ctx->user_bufs ? 0 : -ENOMEM;
1248 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
1249 unsigned int nr_args, u64 __user *tags)
1251 struct page *last_hpage = NULL;
1252 struct io_rsrc_data *data;
1256 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
1260 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
1262 ret = io_rsrc_node_switch_start(ctx);
1265 ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
1268 ret = io_buffers_map_alloc(ctx, nr_args);
1270 io_rsrc_data_free(data);
1274 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
1276 ret = io_copy_iov(ctx, &iov, arg, i);
1279 ret = io_buffer_validate(&iov);
1283 memset(&iov, 0, sizeof(iov));
1286 if (!iov.iov_base && *io_get_tag_slot(data, i)) {
1291 ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
1297 WARN_ON_ONCE(ctx->buf_data);
1299 ctx->buf_data = data;
1301 __io_sqe_buffers_unregister(ctx);
1303 io_rsrc_node_switch(ctx, NULL);
1307 int io_import_fixed(int ddir, struct iov_iter *iter,
1308 struct io_mapped_ubuf *imu,
1309 u64 buf_addr, size_t len)
1314 if (WARN_ON_ONCE(!imu))
1316 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
1318 /* not inside the mapped region */
1319 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
1323 * Might not be a start of buffer, set size appropriately
1324 * and advance us to the beginning.
1326 offset = buf_addr - imu->ubuf;
1327 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
1331 * Don't use iov_iter_advance() here, as it's really slow for
1332 * using the latter parts of a big fixed buffer - it iterates
1333 * over each segment manually. We can cheat a bit here, because
1336 * 1) it's a BVEC iter, we set it up
1337 * 2) all bvecs are PAGE_SIZE in size, except potentially the
1338 * first and last bvec
1340 * So just find our index, and adjust the iterator afterwards.
1341 * If the offset is within the first bvec (or the whole first
1342 * bvec, just use iov_iter_advance(). This makes it easier
1343 * since we can just skip the first segment, which may not
1344 * be PAGE_SIZE aligned.
1346 const struct bio_vec *bvec = imu->bvec;
1348 if (offset <= bvec->bv_len) {
1350 * Note, huge pages buffers consists of one large
1351 * bvec entry and should always go this way. The other
1352 * branch doesn't expect non PAGE_SIZE'd chunks.
1355 iter->nr_segs = bvec->bv_len;
1356 iter->count -= offset;
1357 iter->iov_offset = offset;
1359 unsigned long seg_skip;
1361 /* skip first vec */
1362 offset -= bvec->bv_len;
1363 seg_skip = 1 + (offset >> PAGE_SHIFT);
1365 iter->bvec = bvec + seg_skip;
1366 iter->nr_segs -= seg_skip;
1367 iter->count -= bvec->bv_len + offset;
1368 iter->iov_offset = offset & ~PAGE_MASK;